The invention relates to directional control valves and in particular relates to a valve for selectively connecting alternate fuel supply tanks to a combustion engine.
In automobiles, trucks, and like vehicles propelled by combustion engines, a need for increased fuel carrying capacity has been experienced. Increased capacity can be achieved by installation of an auxiliary or second tank rather than by the substitution of a larger tank for that normally offered by the vehicle manufacturer. Such auxiliary tanks, or in some cases twin tanks, are often preferred or required for a variety of reasons including safety considerations, space limitations in conventional vehicle designs, retrofit installations by dealers and others besides the vehicle manufacturer, and the security offered by a reserve tank. Many constraints and design criteria exist in the specification of a suitable valve for selectively controlling the supply of fuel from multiple tanks. For instance, in certain vehicles the fuel supply circuit includes a return loop for fuel supplied to but not immediately consumed by the engine. The fuel selector valve, then, must include provisions for return of excess fuel to the active tank. Supply and return flow through the valve must be accomplished while keeping the inactive tank isolated from both the engine and the selected tank. The valve should be capable of manual operation, preferably by simple remote actuation. Ideally, the valve design is inexpensive to mass-produce, simple to install, and reliable in operation. In general, prior art devices of the general class under consideration here have been relatively complex and expensive to manufacture.